Polarized relay



March 16, i948. A. c. DAVIS 2,437,726

POLARIZED RELAY Filed Aug. 18, 1944 Patented Mar. 16, 1948 UNITED STATES PATENT OFFICE POLARIZED RELAY Arthur C. Davis, Burbank, Calif.

Application August 18, 1944, Serial No. 550,698

8 Claims. (Cl. 20G-93) The invention relates to a polarized relay wherein an electric current in an input circuit is employed to reverse the polarity of one or more pole pieces or inagnetizable members in order to reverse the direction of movement of a rotatable permanent magnet which controls contacts in an output circuit. Thus, a weak current in the input circuit may control a larger current in the output circuit, to effect the operation of any desired apparatus in the output circuit.

The usual type of polarized relay has no tendency, through the magnetic attraction of the armature by the magnet, when the armature is not magnetized, to assume a neutral position. Hence, it is common to use a spring, which is employed to bias the polarized magnet in its neutral position. This neutral position may, of course, be one where the contacts controlled by the magnet are either open or closed.

An object oi the invention is to provide a polarized relay having magnetizable pole pieces so constructed and arranged that the magnet will assume the neutral position without the use of a spring, although a bias device such as a keeper may be employed if desired.

Another object of the invention is to provide a polarized relay having a construction whereby the electrical contacts may be operated quickly by a snap action, and in a modified form by a more gradual opening and closing movement of the contacts.

Another object of the invention is to simplify and improve the construction of a polarized relay and in particular to provide an improved form of polarized relay embodied in a vacuum tube which may have a conventional base with terminals to t in a socket of the type usually employed for electron discharge devices.

Another object of the invention is to provide a polarized relay having a rotatable magnet which assumes a neutral position providing a path of minimum reluctance with its eld pole when the latter is not magnetized.

For further details of the invention, reference may be made to the drawings, wherein Fig. 1 is a perspective View of one form oi polarized relay according to the invention.

Fig. 2 is a view in elevation with parts broken away of the air gap and one end of the pole pieces and magnet oi the relay of Fig. l.

Fig. 3 is a perspective view of a modification.

Figs. 4 and 5 are views like Fig. 2 of further modincations.

Referring in detail to the drawings, the polarized relay i comprises an evacuated cylindrical glass tube 2 in which is mounted magnet 3 in the shape of a vane mounted for oscillation on the axis of tube 2 and having at its opposite ends shafts l and El which are pivotally mounted in the bearings t and l, respectively, at the opposite ends ofthe tube 2. The shaft 5 carries a movable contact member 8 which is adapted in one position to complete the circuit from fixed contact 9 to the xed contact le, and in the alternate position, to complete the circuit from fixed contact il to the fixed contact I2.

The contacts 9 to I2 are mounted in the lower end of the tube 2 and are connected to suitable output circuits to be controlled.

The permanent magnet 3 is slightly shorter crosswise of the tube 2 than the inside diameter of the circular tube 2 and its opposite ends have opposite polarties as indicated at N and S. On the outside of the tube 2 are arranged two similar soit iron magnetizable arcuate pole pieces I3 and i4, which are separated at their ends by air gaps iti and i5. The air gaps I5 and IG may be somewhat in the shape of a letter V, lying on its side, as indicated in the drawings, or each of these air gaps may slant at forty-live degrees across the end of the magnet 3 as indicated at Il in Fig. 4,

or each air gap may be parallel to the end of magnet 3 as shown at i8 in Fig, 5.

Referring again to Fig. 1, the relay I may be operated by supplying current in one direction or the other from battery or other source I9 and reversing switch 2i) through coil 2l arranged on extensions 22 and 23 of the pole pieces I3 and I4 respectively. Current in coil 2i magnetizes pole piece I3 to be of north polarity when I4 is south and vice versa. When I3 is north, both ends of i3 cause clockwise movement of magnet 3, and

' Iii then being south, both of its ends also cause clockwise movement o magnet 3. Reversal of the polarity of pole pieces I3 and Ii! by operating switch 2) causes movement oi magnet 3 in the reverse direction. Hence four pole tips, that is both ends of both pole pieces I3 and I4 are effective to move magnet 3 in one direction or the'.

other.

The N and S ends of magnet 3, of course, swing in an arc about the axis of bearings 5, 6, i. e., the axis of tube 2 and the pole pieces i3 and I4 extend in a concentric arc on the outside of the tube 2. The pole pieces i3 and Il! are the same in shape, pole piece I3 terminating at one end in a tapered point tapered at sixty degrees, and at the other end in a fork 25 each branch of which Y changes gradually is tapered at thirty degrees. Likewise one end of 4pole piece I4 terminates in a sixty degree tapered point 26 and at the other end in a fork 2'I having thirty degree legs.

The over-al1 circumferential length of each pole-piece I3 and I4 is slightly more than onehalf the circumference of tube 2, whereby when magnet 3 is in neutral position shown, both ends of each pole-piece I3 and I E are in front of one end of magnet 3 which provides a path of low reluctance for lines of force from magnet 3 when relay I is not in use, Also when current in `coil 2| is interrupted, magnet 3 Will move to its neutral position shown in Figs. 1 and 2 because it will move until the reluctance is minimum. The reluctance for any position of magnet 3 beyond neutral is higher because in neutral position the only air gaps in the path `are the air gaps between the N and S ends of magnet 3 radially to the opposite ends of pole-pieces I3 and I4, whereas if magnet 3 is ina position to the right or left of thatshown in Fig. 2, then the magnetic circuit includes the air gaps I5 and I6, resulting in much higher reluctance. To avoid shunting out the gaps I5 and I6, the pole extensions 22 and 23 are separated by an air gap 28.

In the neutralv position in Fig.V 2, the area of pole 26 directly in front of the end of magnet 3 is the same as thesums of the areas Iof the branches of fork 25 directly in front of magnet 3 and the same is true at the other end of magnet 3. Also in this position the area of the tip 29 to the left of magnet 3 equals the sum of the areas of tips 30 and 3i to the right of magnet 3 and the same is true ofeach end of magnet 3 when in neutral position. Somewhat the same condition is true of the forty-ve degree air gap I 'I in Fig. 4. Hence magnet 3 is magnetically balanced when in neutral position.

In the form shown in Fig. 5, the end of magnet 3 centers in the air gap I8 when magnet 3 is in neutral position, the opposite end of magnet 3 also appearing as shown in Fig. 5. In this case, each pole piece 32 and 33 is slightly less than a half circle. When magnet 3 is in a position to the right or left of that shown in Fig. 5, as in the other figures, the reluctance is high and includes not only the air gaps between the magnet 3 and the pole pieces such as 32,Y 33, but also the airv gaps between the ends of pole pieces 32, 33. Hence magnet 3 as before will automatically move to the neutral position shown in Fig. 5 when pole pieces 32, 33 are not magnetized or are de-magnetized.

As magnet 3 moves from neutral position when the pole pieces are magnetized, this movement willfbe sudden, like a snap action with the construction in Fig. 5 as the change in reluctance is high for small movements of the magnet, whereas the acceleration of magnet 3 is more gradual with the form in Figs. 1 and 2 and the reluctance the magnetized pole pieces. Y

The soft iron extensions 22 and 23 may be arranged at one side of the tube 2 which may have a conventional base with usual contact prongs connected to contacts 9-I2, Or the base may house the coil 2| and extensions 22, 23. As shown in Fig. 3, one may dispense with the air gap 28 in Fig. 1 and magnetically connect the armatures 34, 35 together by soft iron core 36 on which the control coil 38 is arranged. In this case the magnet V35 has a reduced tendency to seek its neutral position when pole pieces 311 and 35 are not magnetized, and hence a keeper 40, rotatably mounted when magnet 3 is moved by on spindle 4I, may be employed to adjust magnet 39 to its neutral position, but being overcome by pole pieces 3a and 35 when the latter are magnetized.

Various other modifications may be made in the invention without departing from the spirit of the following claims.

I claim:

1. A polarized relay comprising a circular vacuum tube having an axis, a polarized vane in said tube, contacts in said tube controlled thereby, means supporting said vane for movement about said axis, a pair of arcuate pole pieces arranged end to end around said tube and around said vane concentric with said axis, the adjacent ends of said pole pieces being separated by air gaps at opposite sides of said tube, said pole pieces having extensions beyond said tube, an air gap between said extensions, and coil means on said extensions for oppositely magnetizing said pole pieces. Y

2. A polarized relay according to claim 1 wherein said air gaps are each substantially in the shape of the letter V lying crosswise of said axis, said vane having opposite ends narrower than the length of said air gaps around said axis.

3. A polarized relay according to claim 1, wherein said air gaps are each substantially parallel to said axis.

4. A polarized relay according to claim 1, wherein said pole pieces have extensions separated by an additional air gap to prevent shunting the flux from said vane when said coil means is de-energized.

5. A polarized relay according to claim 1, wherein each of said air gaps slant-s with respect to said axis, said vane having ends narrower than the length of said gaps around said axis.

6. A polarized relay comprising a vacuum tube having therein a movable polarized armature having opposite ends, means supporting said armature for movement about an axis, Contacts in said tube controlled by said armature, said armature having a neutral position and an operative position in opposite directions therefrom,

a pair of soft iron arcuate pole pieces arranged end to end around said tube and around said armature, the adjacent ends of said pole pieces being separated by air gaps at opposite sides of said tube, extensions on said pole pieces beyond said tube, and a coil on said extensions for reversing the movement of said armature, said pole pieces and air gaps being constructed and arranged to provide for said armaturea different reluctance for dierent armature positions Sullicient to restore said armature to neutral position when said coil is de-energized.

7. A polarized relay comprising a vacuum tube, contacts in said tube, a movable permanent magnet in'said tube for operating said contacts, said magnet having a neutral position and an operative position in opposite directions therefrom, means supporting said magnet for movement about an axis, stationary magnetic pole pieces of low residual induction outside of said tube, said pole pieces having overlapping ends separated by an air gap, a coil outside of said tube for energizing said pole pieces to operate certain of said contacts in either of said operative positions, said pole pieces and said movable magnet constituting means for automatically, magnetically restoring said movable magnet to neutral position when said coil is de-energized.

8. A polarized relay according to claim 7 wherein said movable magnet has opposite poles at opposite ends of a diameter of said axis, and said pole pieces have overlapping ends separated UNITED STATES PATENTS by an air gap at opposite ends of a diameter of said axis, the area of overhang of each of said Number Name Date pole pieces at the same end of said magnet being 5 481,617 Freeman Alg- 301 1392 the same when said magnet is in neutral position. 5491501 Depuy N0V 12 1895 ARTHUR C. DAVIS 570,454 Coleman Nov. 3, 1896 2,012,153 Bates Aug. 20, 1935 REFERENCES CITED 2,175,046 Warner Oct. 3, 1939 2,245,391 Dickten June 10, 1941 The following references are of record in the 10 2,264,022 Elwood Nov' 25 1941 111e of this patent: 

